Each day 500 inventory control records are cycle-counted for errors. These counts have been made over a period of 20 days and have resulted in the following proportion of records found in error each day: a. Calculate the center line, upper control limit, and lower control limit for a p control chart. b. Plot the 20 points on the chart and determine which ones are in control. c. Is the process stable enough to begin using these data for quality control purposes? SOLUTION a Answer NAME: SECTION: CHAPTER 9, key ******** PROBLEM 3 26-Apr-10 Enter sample size for each sample Enter the number of samples taken 500 20 Enter the proportion of records found in error each day in cells B33 through B42 and C33 through C42. _ P 0.0111 0.0025 0.0150 Center Line Upper Control 0.0075 0.0050 Limit Lower Control UCL 0.0252 0.0050 0.0150 0.0125 0.0100 0.0050 0.0025 0.0175 0.0150 0.0125 0.0075 0.0150 0.0250 0.0125 0.0075 Limit LCL 0.0000 TO VIEW THE OTHER AREAS OF THIS WORKSHEET, PRESS THE "PAGE DOWN" AND "PAGE UP" KEYS OR USE THE VERTICAL SCROLL BAR. 0.0200 0.0100 b All points are in control (the UCL is .0252 and the nearest point is .0250) c. Since all 20 points are in control, the process is stable enough for quality control purposes